Does the epidermal growth factor receptor play a role in the progression of thyroid cancer?

Spectrum of EGFR mutation and its relation with high-risk predictors in thyroid cancer in Kashmiri population: 2 years prospective study at a tertiary care hospital

Background

EGFR mutation has not been extensively studied in thyroid cancer. This study was conducted to study spectrum of EGFR mutation in thyroid cancer in Kashmiri population for possible therapeutic purpose.

Methods

It was 2 years prospective cross-sectional study conducted at a tertiary care center in which histologically confirmed, untreated thyroid cancers were included. These specimens were subjected to EGFR mutation analysis by AS-PCR method.

Results

There were a total 60 patients with preponderance of females [44(73%) vs 16(27%)]. Most were in the age group of less than 45 years (75%). Most of these patients were non-smokers [50(83.3%) vs 10 (17.3%)]. Papillary thyroid carcinoma (PTC) was the commonest type 48(80%), rest was follicular type (FTC) 12(20%). Well-differentiated carcinoma (WDC) was common than poorly differentiated (PDC) [41(68.4%) vs 19 (31.6%)]. Lymph node metastasis and vascular invasion were present in 32 (53.4%) and 17 (28.4%) respectively. Thirty-two (53.3%) patients were having 15 bp deletion in exon 19 of EGFR. These deletions were common in PTC than FTC, 29(60.5%) vs 3(25%) which was statistically significant (p = 0.04, CI = 0.2). The total mutational rate of T790M in EGFR tyrosine kinase domain (exon 20) was found to be only 8.4% (5 of 60). Only 4 (8.3%) of these mutations were detected in PTC and rest in FTC (1 of 12). Twenty-six (43.3%) of exon 21 were positive for L858R mutation in EGFR tyrosine kinase domain. Married persons and PDC were significant predictors of L858R mutation in EGFR tyrosine kinase domain in thyroid cancer as this was statistically significant in them with p = 0.04, 0.03 respectively.

Conclusion

In our population, PTC is common in females with half of population harboring EGFR mutation and it is statistically significant in poorly differentiated carcinoma and in married individuals.

It implies that EGFR may be used in thyroid cancer as a possible therapeutic agent in our set of population.

Advances in pharmacotherapy for advanced thyroid cancer of follicular origin (PTC, FTC). New approved drugs and future therapies

INTRODUCTION

The most common altered signaling found in aggressive iodine-refractory Thyroid cancer derived from follicular cells (RAI-TC) are RTK, MAPK, PI3K, WNT, BRAF, RAS, RET, and TP53. Tyrosine Kinase Inhibitors (TKI) are multi-kinase inhibitors able to act against different pathways, that elicit an anti-neoplastic activity.

AREAS COVERED

The aim of this paper is to review recent novel molecular therapies of RAI-TC. Recently, sorafenib and lenvatinib, have been approved for the treatment of aggressive RAI-TC. Other studies are evaluating vandetanib and selumetinib in RAI-TC. Furthermore, preliminary studies have evaluated dabrafenib, and vemurafenib in BRAF mutated RAI-TC patients to re-induce 131-iodine uptake. The interplay between cells of the immune system and cancer cells can be altered by immune checkpoints inhibitors. The expression of PDL1 in RAI-TC was related to tumor recurrence and poor survival. Several clinical trials are investigating a combination of different therapies, such as lenvatinib and pembrolizumab.

EXPERT OPINION

Mechanisms of resistance to TKIs inhibitors can be of intrinsic or acquired origin. An acquired resistance to lenvatinib, or sorafenib can be due to upregulation of FGFR; therefore anti-FGFR agents are evaluated. A new strategy is to combine TKIs with immunotherapy. Several studies are evaluating lenvatinib and pembrolizumab in RAI-TC patients.

Molecular targets of tyrosine kinase inhibitors in thyroid cancer

Thyroid cancer (TC) is the eighth most frequently diagnosed cancer worldwide with a rising incidence in the past 20 years. Surgery is the primary strategy of therapy for patients with medullary TC (MTC) and differentiated TC (DTC). In DTC patients, radioactive iodine (RAI) is administered after thyroidectomy. Neck ultrasound, basal and thyroid-stimulating hormone-stimulated thyroglobulin are generally performed every three to six months for the first year, with subsequent intervals depending on initial risk assessment, for the detection of possible persistent/recurrent disease during the follow up. Distant metastases are present at the diagnosis in ∼5 % of DTC patients; up to 15 % of patients have recurrences during the follow up, with a survival reduction (70 %-50 %) at 10-year. During tumor progression, the iodide uptake capability of DTC cancer cells can be lost, making them refractory to RAI, with a negative impact on the prognosis. Significant advances have been done recently in our understanding of the molecular pathways implicated in the progression of TCs. Several drugs have been developed, which inhibit signaling kinases or oncogenic kinases (BRAF^V600E, RET/PTC), such as those associated with Platelet-Derived Growth Factor Receptor and Vascular Endothelial Growth Factor Receptor. Tyrosine kinase receptors are involved in cancer cell proliferation, angiogenesis, and lymphangiogenesis. Several tyrosine kinase inhibitors (TKIs) are emerging as new treatments for DTC, MTC and anaplastic TC (ATC), and can induce a clinical response and stabilize the disease. Lenvatinib and sorafenib reached the approval for RAI-refractory DTC, whereas cabozantinib and vandetanib for MTC. These TKIs extend median progression-free survival, but do not increase the overall survival. Severe side effects and drug resistance can develop in TC patients treated with TKIs. Additional studies are needed to identify a potential effective targeted therapy for aggressive TCs, according to their molecular characterization.

Primary cell cultures for the personalized therapy in aggressive thyroid cancer of follicular origin

Thyroid cancer (TC) is the most prevalent endocrine malignancy. More than 90 % of TC is represented by differentiated TC (DTC) arising from the follicular thyroid cells. DTC includes papillary TC (PTC), follicular TC (FTC), and Hürthle cell TC. Anaplastic TC (ATC) accounts for 1% of TC, and it represents 15-40 % of TC death. Current treatment strategies are not completely effective against aggressive DTC or ATC, and mortality is one of the most important challenges. Recently, progresses have been obtained in the understanding of the molecular/genetic basis of TC progression, and new drugs have been introduced [i.e. tyrosine kinase inhibitors (TKIs)], able to block the oncogenic or signaling kinases, associated with cellular growth. Thyroid cell lines, obtained from tumoral cells and chosen for high proliferation in vitro, have been used as preclinical models. Actually, these cells lose the characteristic features of the primary tumor, because they adapt to in vitro growth conditions. For these reasons, the use of these cell lines has important limitations, and more recently human primary cell cultures have been established as monolayer cultures, and investigated for their biological behavior. Moreover, in the past, primary TC cells could be collected only through surgical biopsies, while recently human primary cell cultures can be established also from samples of fine-needle aspiration citology from aggressive dedifferentiated DTC or ATC. Testing in vitro different TKIs in each patient can help to develop new personalized treatments, without using ineffective drugs. In conclusion, personalized medicine and precise oncology, which consider both patients and their disease features, represent the future of the treatment approach, and further progress is needed in this direction.

Novel treatments for anaplastic thyroid carcinoma

Anaplastic thyroid cancer (ATC) is one of the deadliest human cancers and it is less than 2% of thyroid carcinomas (TCs). The standard treatment of ATC includes surgical debulking, accelerated hyperfractionated external beam radiation therapy (EBRT), and chemotherapy, in particular with cisplatin or doxorubicin, achieving about 10 months of median survival. Since ATC is a rare and aggressive tumor, it is still challenging to predict the patient clinical therapy responsiveness. Several genetic mutations have been described in ATC, involved in different molecular pathways linked to tumor progression, and novel therapies acting on these molecular pathways have been investigated, to improve the quality of life in these patients. Here we review the new targeted therapy of ATC. We report interesting results obtained with molecules targeting different pathways: angiogenesis (vandetanib, combretastatin, sorafenib, lenvatinib, sunitinib, CLM94, CLM3, etc.); EGFR (gefitinib, docetaxel); BRAF (dabrafenib/trametinib, vemurafenib); PPARγ agonists (rosiglitazone, pioglitazone, efatutazone); PD-1 and PD-L1 (pembrolizumab); TERT. To escape resistance to monotherapies, the evaluation of combination strategies with radiotherapy, chemotherapy, or targeted drugs is ongoing. The results of clinical trials with dabrafenib and trametinib led to the approval from FDA of this combination for patients with BRAF V600E mutated ATC with locally advanced, unresectable, or metastatic ATC. The anti-PD-L1 antibody immunotherapy, alone or combined with a BRAF inhibitor, has been shown also promising in the treatment of ATC. Furthermore, to increase the therapeutic success and not to use ineffective or even harmful treatments, a real tailored therapy should be pursued, and this can be achieved thanks to the new available genomic analysis methods and to the possibility to test in vitro novel treatments directly in primary cells from each ATC patient. Exploring new treatment strategies is mandatory to improve the survival of these patients, guaranteeing a good quality of life.

Molecular testing in the diagnosis of differentiated thyroid carcinomas

Different genetic mutations and other molecular alterations in papillary thyroid cancer (PTC) and follicular thyroid cancer (FTC) can be detected in fine-needle aspiration (FNA) of thyroid nodules, and can be used successfully to ameliorate cancer diagnosis and management of patients with thyroid nodules. The greatest experience has been obtained with the diagnostic use of BRAF mutation that is strongly specific for malignancy when detected using well-validated techniques. The strongest diagnostic result can be obtained testing FNA samples for a panel of mutations that typically involve TERT, BRAF, PAX8/PPARγ, RAS, and RET/PTC. Finding any of these mutations in a thyroid nodule provides strong indication for malignancy and helps to refine clinical management for a significant proportion of patients with indeterminate cytology. The use of molecular markers, as TERT, BRAF, PAX8/PPARγ, RAS, and RET/PTC, may be considered for patients with indeterminate FNA cytology (FNAC) to help guide management. In patients with indeterminate TIR3 FNA, the combination of precise molecular marker expression analysis with molecular mutations evaluations could ameliorate significantly the accuracy of cancer diagnosis. However other prospective studies are needed to identify more accurate molecular markers. Finally, the knowledge of these molecular pathways has permitted the development of new targeted therapies for aggressive TC.

Novel treatment options for anaplastic thyroid cancer

Several genetic alterations have been identified in different molecular pathways ofanaplastic thyroid cancer (ATC) and associated with tumor aggressiveness and progression (BRAF, p53,RAS, EGFR, VEGFR-1, VEGFR-2, etc). New drugs targeting these molecular pathways have beenrecently evaluated in ATC. Areas covered: We review the new targeted therapies of ATC. Interesting results have been reported with molecules targeting different pathways, as: a-BRAF (dabrafenib/trametinib, vemurafenib); b-angiogenesis (sorafenib, combretastatin, vandetanib, sunitinib, lenvatinib, CLM3, etc); c-EGFR (gefitinib); d- PPARγ agonists (rosiglitazone, pioglitazone, efatutazone). In patients with ATC treated with lenvatinib, a median overall survival of 10.6 (3.8-19.8) months was reported. In order to bypass the resistance to the single drug, the capability of targeted drugs to synergize with radiation, or chemotherapy, or other targeted drugs is explored. Expert commentary: New, affordable and individual genomic analysis combined with the opportunity to test these new treatments in primary cell cultures from every ATC patient in vitro, may permit the personalization of therapy. Increasing the therapeutic effectiveness and avoiding the use of ineffective drugs. The identification of new treatments is necessary, to extend life duration guaranteing a good quality of life. To bypass the resistance to asingle drug, the capability of targeted drugs to synergize with radiation, or chemotherapy, or othertargeted drugs is explored. Moreover, new affordable individual genomic analysis and the opportunity totest these novel treatments in primary cell cultures from every ATC patient in vitro, might permit topersonalize the therapy, increasing the therapeutic effectiveness and avoiding the use of ineffectivedrugs.

Novel therapeutic clues in thyroid carcinomas: The role of targeting cancer stem cells

Thyroid carcinomas (TCs), the most common endocrine tumors, represent the eighth most common cancer diagnosed worldwide in both women and men. To treat these malignancies, several drugs are now available and a number of novel ones have been enrolling in clinical trials, addressing both oncogenic pathways in cancer cells and angiogenic pathways in tumor endothelial cells. However, their use is not devoid of serious toxicities and their efficacy is limited, being dependent on carcinoma typology and the occurrence of acquired resistance. Accordingly, it is time to recast therapeutic strategies against these types of tumors to get to newer and fully effective drugs. In this perspective, latest findings demonstrate that cancer stem cells (CSCs) represent a challenging target to strike. They possess core traits of self-renewal and differentiation, being resistant to the effects of chemotherapy and radiation and playing a key role in mediating metastasis. Therefore, basic molecular elements sustaining both development of thyroid cancer stem cells and their residence in the stemness condition represent a set of innovative and still unexplored targets to address. In this review, a thorough literature survey has been accomplished, to take stock of mechanisms governing thyroid carcinomas and to point out both their currently available treatments and the novel forthcoming ones. Pubmed, Scifinder and ClinicalTrials.gov were exploited as research applications and registry database, respectively. Original articles, reviews, and editorials published within the last ten years, as well as open clinical investigations in the field, were analyzed to suggest new exciting therapeutic opportunities for people affected by TCs.

Prognostic value of survivin and EGFR protein expression in triple-negative breast cancer (TNBC) patients

Triple-negative breast cancer (TNBC) is a particular type of breast cancer which is characterized by its biological aggressiveness, worse prognosis, and lack of prognostic markers or therapeutic targets in contrast with hormonal receptor-positive and human epidermal growth factor receptor 2-positive (HER2+) breast cancers. We aimed to evaluate survivin and epidermal growth factor receptor (EGFR) expression and their prognostic value and determine their relationships with the clinicopathological parameters of TNBC. A total of 136 patients who had undergone a resection of primary TNBC were enrolled at the Third Affiliated Hospital of Harbin Medical University from March 2003 to September 2005. Expression of ER, PR, HER2, EGFR, and survivin was assessed by immunohistochemistry. The association of TNBC and other clinicopathological variables and the prognostic value of survivin and EGFR expression were evaluated. Survivin was expressed in 62 (45.6 %) cases and EGFR was expressed in 82 (60.3 %) cases. Survivin expression was associated with menopausal status (P = 0.011), tumor size (P = 0.037), and lymph node status (P = 0.001). EGFR expression was associated with menopausal status (P = 0.029), lymph node status (P = 0.004), P53 expression (P = 0.001), Ki-67 expression (P = 0.028), and lymphatic vascular invasion (P = 0.037). A multivariate analysis demonstrated that tumor size (hazard ratio (HR) 1.587, 95 % confidence interval (CI) 1.081–2.330, P = 0.018 for disease-free survival (DFS); HR 1.606, 95%CI 1.096–2.354, P = 0.015 for overall survival (OS)), lymph node status (HR 2.873, 95%CI 1.544–5.344, P = 0.001 for DFS; HR 2.915, 95%CI 1.553–5.471, P = 0.001 for OS), tumor grade (HR 1.914, 95%CI 1.218–3.007, P = 0.005 for DFS; HR 1.983, 95%CI 1.228–3.203, P = 0.005 for OS), EGFR (HR 3.008, 95%CI 1.331–6.792, P = 0.008 for DFS; HR 3.151, 95%CI 1.374–7.226, P = 0.007 for OS), and survivin (HR 1.573, 95%CI 1.087–2.277, P = 0.016 for DFS; HR 1.607, 95%CI 1.088–2.374, P = 0.017 for OS) were of prognostic significance for disease-free and overall survival. We draw a conclusion from the present study that survivin and EGFR expression are useful prognostic markers of TNBC and might be useful for molecular targeting therapy of TNBC treatment.

Selective use of vandetanib in the treatment of thyroid cancer

Vandetanib is a once-daily orally available tyrosine kinase inhibitor that works by blocking RET (REarranged during Transfection), vascular endothelial growth factor receptor (VEGFR-2, VEGFR-3), and epidermal growth factor receptor and to a lesser extent VEGFR-1, which are important targets in thyroid cancer (TC). It is emerging as a potentially effective option in the treatment of advanced medullary thyroid cancer (MTC) and in dedifferentiated papillary thyroid cancer not responsive to radioiodine. The most important effect of vandetanib in aggressive MTC is a prolongation of progression-free survival and a stabilization of the disease. Significant side effects have been observed with the vandetanib therapy (as fatigue, hypertension, QTc prolongation, cutaneous rash, hand-and-foot syndrome, diarrhea, etc), and severe side effects can require the suspension of the drug. Several studies are currently under way to evaluate the long-term efficacy and tolerability of vandetanib in MTC and in dedifferentiated papillary TC. The efficacy of vandetanib in patients with MTC in long-term treatments could be overcome by the resistance to the drug. However, the effectiveness of the treatment could be ameliorated by the molecular characterization of the tumor and by the possibility to test the sensitivity of primary TC cells from each subject to different tyrosine kinase inhibitor. Association studies are evaluating the effect of the association of vandetanib with other antineoplastic agents (such as irinotecan, bortezomib, etc). Further research is needed to determine the ideal therapy to obtain the best response in terms of survival and quality of life.

Tyrosine kinase inhibitors for the therapy of anaplastic thyroid cancer

Anaplastic thyroid cancer (ATC) is often incurable so new therapeutic approaches are needed. Tyrosine kinases inhibitors (such as imanitib, sunitinib or sorafenib) are under evaluation for the treatment of ATC. Other vascular disrupting agents, such as combretastatin A4 phosphate, and antiangiogenic agents, such as aplidin, PTK787/ZK222584 and human VEGF monoclonal antibodies (bevacizumab, cetuximab), have been evaluated. Small-molecule adenosine triphosphate competitive inhibitors directed intracellularly at EGFRs tyrosine kinase, such as erlotinib or gefitinib, are also studied. Furthermore, new molecules have been shown to be active against ATC, such as CLM94 and CLM3. However, more research is needed to finally identify therapies able to control and to cure this disease.

New therapies for dedifferentiated papillary thyroid cancer

The number of thyroid cancers is increasing. Standard treatment usually includes primary surgery, thyroid-stimulating hormone suppressive therapy, and ablation of the thyroid remnant with radioactive iodine (RAI). Despite the generally good prognosis of thyroid carcinoma, about 5% of patients will develop metastatic disease, which fails to respond to RAI, exhibiting a more aggressive behavior. The lack of specific, effective and well-tolerated drugs, the scarcity of data about the association of multi-targeting drugs, and the limited role of radioiodine for dedifferentiated thyroid cancer, call for further efforts in the field of new drugs development. Rearranged during transfection (RET)/papillary thyroid carcinoma gene rearrangements, BRAF (B-RAF proto-oncogene, serine/threonine kinase) gene mutations, RAS (rat sarcoma) mutations, and vascular endothelial growth factor receptor 2 angiogenesis pathways are some of the known pathways playing a crucial role in the development of thyroid cancer. Targeted novel compounds have been demonstrated to induce clinical responses and stabilization of disease. Sorafenib has been approved for differentiated thyroid cancer refractory to RAI.

Molecular Targeted Therapies of Aggressive Thyroid Cancer

Differentiated thyroid carcinomas (DTCs) that arise from follicular cells account >90% of thyroid cancer (TC) [papillary thyroid cancer (PTC) 90%, follicular thyroid cancer (FTC) 10%], while medullary thyroid cancer (MTC) accounts <5%. Complete total thyroidectomy is the treatment of choice for PTC, FTC, and MTC. Radioiodine is routinely recommended in high-risk patients and considered in intermediate risk DTC patients. DTC cancer cells, during tumor progression, may lose the iodide uptake ability, becoming resistant to radioiodine, with a significant worsening of the prognosis. The lack of specific and effective drugs for aggressive and metastatic DTC and MTC leads to additional efforts toward the development of new drugs. Several genetic alterations in different molecular pathways in TC have been shown in the past few decades, associated with TC development and progression. Rearranged during transfection (RET)/PTC gene rearrangements, RET mutations, BRAF mutations, RAS mutations, and vascular endothelial growth factor receptor 2 angiogenesis pathways are some of the known pathways determinant in the development of TC. Tyrosine kinase inhibitors (TKIs) are small organic compounds inhibiting tyrosine kinases auto-phosphorylation and activation, most of them are multikinase inhibitors. TKIs act on the aforementioned molecular pathways involved in growth, angiogenesis, local, and distant spread of TC. TKIs are emerging as new therapies of aggressive TC, including DTC, MTC, and anaplastic thyroid cancer, being capable of inducing clinical responses and stabilization of disease. Vandetanib and cabozantinib have been approved for the treatment of MTC, while sorafenib and lenvatinib for DTC refractory to radioiodine. These drugs prolong median progression-free survival, but until now no significant increase has been observed on overall survival; side effects are common. New efforts are made to find new more effective and safe compounds and to personalize the therapy in each TC patient.

Personalization of targeted therapy in advanced thyroid cancer

Although generally the prognosis of differentiated thyroid carcinoma (DTC) is good, approximately 5% of people are likely to develop metastases which fail to respond to radioactive iodine, and other traditional therapies, exhibiting a more aggressive behavior. Nowadays, therapy is chosen and implemented on a watch-and-wait basis for most DTC patients. Which regimen is likely to work best is decided on the basis of an individual's clinical information, but only data referring to outcomes of groups of patients are employed. To predict the best course of therapy, an individual patient's biologic data is rarely employed in a systematic way. Anyway, the use of not expensive individual genomic analysis could lead us to a new era of patient-specific and personalized care. Recently, key targets that are now being evaluated in the clinical setting have been evidenced in the pathogenesis of these diseases. Some of the known genetic alterations playing a crucial role in the development of thyroid cancer include B-Raf gene mutations, rearranged during transfection/ papillary thyroid carcinoma gene rearrangements, and vascular endothelial growth factor receptor-2 angiogenesis pathways. The development of targeted novel compounds able to induce clinical responses and stabilization of disease has overcome the lack of effective therapies for DTC, which are resistant to radioiodine and thyroid stimulating hormone-suppressive therapy. Interestingly, the best responses have been demonstrated in patients treated with anti-angiogenic inhibitors such as vandetanib and XL184 in medullary thyroid cancer, and sorafenib in papillary and follicular DTC.

Epidermal growth factor receptor overexpression is a marker for adverse pathologic features in papillary thyroid carcinoma

BACKGROUND

Epidermal growth factor receptor (EGFR) overexpression (EGFR-H) is implicated in thyroid carcinoma disease progression; however, the clinicopathologic significance of EGFR-H in tumors that harbor EGFR and/or v-Raf murine sarcoma viral oncogene homolog B1 (BRAF)(V600E) mutations is unknown.

METHODS

Tissue microarrays from 81 patients who had undergone thyroidectomy for carcinoma from 2002-2011 were scored for EGFR expression using immunohistochemistry. Somatic mutations in EGFR exons 19 and 21 and BRAF were analyzed. Correlations between the EGFR immunohistochemistry, EGFR, and BRAF(V600E) mutations and the clinicopathologic features were assessed.

RESULTS

EGFR-H was detected in 39.5% of carcinomas (n = 32) from patients with papillary (PTC, 46.2%, n = 18), follicular (29.6%, n = 8), and anaplastic (100.0%, n = 6) but not medullary (0.0%, n = 9) thyroid carcinoma. BRAF(V600E) mutations were identified in 22.2% of the carcinoma cases (n = 18, 15 PTCs and 3 anaplastic thyroid carcinomas). No somatic EGFR mutations were detected in any subtype. On PTC univariate analysis, EGFR-H correlated with increasing stage, extrathyroid extension, tumor capsule invasion, adverse pathologic features (any demonstration of extrathyroid extension, tumor capsule invasion, lymphovascular invasion, lymph node metastasis, and/or distant metastasis), and BRAF(V600E) mutations. On multivariate analysis, EGFR-H correlated with BRAF(V600E) mutations. In BRAF wild-type PTCs, the correlation between EGFR-H and adverse pathologic features approached statistical significance (P = 0.065).

CONCLUSIONS

EGFR-H could be an important biomarker for aggressive PTCs, particularly in BRAF wild-type PTCs. Despite EGFR-H in PTC, follicular thyroid carcinoma, and anaplastic thyroid carcinoma by immunohistochemistry, somatic EGFR mutations were absent. Therefore, future investigations of EGFR should consider histologic and immunohistochemical methods, in addition to molecular profiling of thyroid carcinomas. This multimodal approach is particularly important for future clinical trials testing anti-EGFR therapy.